REPORT ON THE AMPHIPODA. 1443 



a little longer than the fourth, the hind margin finely and obliquely pectinate, and with 

 five hair-like spinules standing out at right angles to the margin ; the finger more than 

 one-third the length of the first joint, strongly bent at the tip. 



Second Peraeopods very similar to the first, but with the side-plates a little less 

 shallow in front, the first joint less slender, the third joint larger, with the two indents 

 of the hind margin more marked, the fourth joint also larger, equalling the length of the 

 fifth, which is itself rather longer than in the first perteopods. 



Third Peneopods. — The side-plates produced in advance of the main framework of 

 the segment, from which they are in this and the two next pairs very indistinctly 

 separated. Branchial vesicles broad, irregular in shape, not quite so long as the first 

 joint. Marsupial plates narrow, longer than the first joint. The first joint entirely free 

 from the side-plate, muscular, widening downwards, channelled behind, the hind margins 

 nearly straight, the front slightly convex below, sparingly serrate ; the second joint 

 not longer than broad, channelled behind, with one apex squared, the front margin a 

 little serrate; the third joint little longer than the second but much wider, the front 

 margin oblique with a sharp apex, the lower margin sinuous ; the fourth joint very large 

 and muscular, longer than the first joint, widest near the base, not twice as long as broad, 

 the hind margin slightly convex, with a small apical tooth, the front margin cut into 

 fifteen oblique teeth, the first a long one with a little denticle high up on its front ; 

 this is followed by three short, a long, four short, a long, and five short teeth, of these 

 five the middle one being the longest ; between the last of these and the apical tooth of 

 the hind margin is the curved hinge of the narrow fifth joint, which is of almost even 

 breadth throughout, and when closing upon the hand-like fourth joint just crosses beyond 

 the tip of its second long tooth ; almost continuous with the margins of the fifth joint 

 are those of the finger, wdiich is long, tapering, and in its distal half much curved ; it is 

 over half the length of the fifth joint, the two together being longer than the fourth. 



Fourth Pereeopods. — Branchial vesicles distally very broad. The first joint not so 

 massive but as broad and nearly as long as in the preceding pair, the greatest breadth 

 near the middle, the hind margin forming an angle (very slightly rounded) at the top, 

 then running in a straight course to the distal end, the front margin convex, the lower 

 part with five indents and a little apical point ; the second joint angled behind, and 

 having one indent in front ; the third joint much longer than the second, the front 

 margin with two indents and an apical tooth, the hind margin with one or two 

 minute indents, and a long decurrent apical tooth ; the fourth joint a little longer 

 than the third including the apical tooth, its hind margin having two minute indents 

 and a small apical tooth, its front margin cut into six teeth, of which the first, third, 

 and fifth are scarcely more than serration ; the fifth joint as long as, or a little longer 

 than, the fourth, slender, slightly curved, the front margin pectinate ; the finger slender, 

 about one-third the length of the fifth joint, the end much curved. 



